Prince Charles has told Sky News that overfishing is "madness" and we must manage our oceans in order to avoid "total disaster".

Following his keynote speech at the Our Ocean conference in Malta, he said that action should have been taken "a long time ago".

Prince Charles said: "What you need to do is organise the fishing in a way that enables fish to survive in their ecosystems.

"It's no good just letting people fish everywhere with bigger and bigger boats and cleverer and cleverer technology to suck up every last fish. That's crazy. That's not conservation, it's madness."

:: To get involved in Sky Ocean Rescue, visit the campaign website here.

Image:Prince Charles helps release turtles in Malta

He added: "You don't have to stop fishing, you have to do it in a way that will actually produce more fish for us all. By managing it properly."

Earlier in the day, Prince Charles praised the "difficult decision" Canada made 25 years ago to sacrifice fishing industry jobs in order to protect northern cod stocks.

He said that while the action "ended more than 400 years of fishing tradition and put over 30,000 people out of work overnight", it succeeded in reviving falling cod stocks.

Acknowledging that it was "unimaginably painful at the time", Prince Charles said it showed that "given a chance, and with some brave decisions, the ocean can recover its health and by doing so generate employment and economic growth".

The World Trade Organisation will be tackling the issue of fisheries subsidies - some of which have been blamed for contributing to overcapacity and overfishing - later this year.

As part of the Ocean Rescue campaign, Sky will remove all single-use plastics from its operations, products and supply chain by 2020 - a pledge Prince Charles described as "fantastic" and a "real example to set".

Stressing the importance of alternatives to plastic in our everyday lives, he said: "All the chemicals used in the making of plastic end up in our own bodies… It all comes back into food chain."

Prince Charles also discussed climate change, which he said was becoming "ever more fearsome", warming up the ocean, causing "terrifying storms" and raising sea levels.

Looking at the "human tragedy" caused by such change, the prince gave a stark warning: "What I've been saying for all these years is don't wait until it's a total disaster before you do something."

During his speech, Prince Charles described his "mounting despair" over plastic pollution - asking the conference: "How will future generations ever forgive us if through our actions we destroy the natural world?"

:: Sky is running a dedicated Sky Ocean Rescue 'pop-up' channel giving viewers the chance to watch live events and panels from the EU Our Ocean conference in Malta.

Watch Our Ocean Rescue channel in the UK (channel 566), Germany (channel 384), Italy (channel 505) and on Virgin (244). It is also available to view via the Sky News website and the Sky News YouTube channel.